Required Practical 4: Food Tests

🧪 Required Practical 4: Food Tests

Testing for biological molecules in food samples:

Benedict's Test (Reducing Sugars)

• Reagent: Benedict's solution (blue)
• Method: Add Benedict's, heat in water bath (80°C)
• Positive result: Blue → green → yellow → orange → brick red
• Tests for: Glucose, fructose, maltose

Iodine Test (Starch)

• Reagent: Iodine solution (orange/brown)
• Method: Add a few drops to sample
• Positive result: Orange → blue-black
• Negative result: Stays orange

Biuret Test (Proteins)

• Reagent: Biuret solution (blue)
• Method: Add biuret solution to sample
• Positive result: Blue → purple
• Negative result: Stays blue

Emulsion Test (Lipids)

• Reagent: Ethanol and water
• Method: Dissolve in ethanol, then add water
• Positive result: White cloudy emulsion forms
• Negative result: Solution stays clear